package protocol

import (
	"context"
	"crypto/ecdsa"
	"errors"
	"fmt"

	"github.com/golang/protobuf/proto"
	"go.uber.org/zap"

	"github.com/status-im/status-go/deprecation"
	"github.com/status-im/status-go/eth-node/crypto"
	"github.com/status-im/status-go/eth-node/types"
	"github.com/status-im/status-go/logutils"
	multiaccountscommon "github.com/status-im/status-go/multiaccounts/common"
	"github.com/status-im/status-go/protocol/common"
	"github.com/status-im/status-go/protocol/protobuf"
	"github.com/status-im/status-go/protocol/requests"
	"github.com/status-im/status-go/protocol/transport"
)

const outgoingMutualStateEventSentDefaultText = "You sent a contact request to @%s"
const outgoingMutualStateEventAcceptedDefaultText = "You accepted @%s's contact request"
const outgoingMutualStateEventRemovedDefaultText = "You removed @%s as a contact"
const incomingMutualStateEventSentDefaultText = "@%s sent you a contact request"
const incomingMutualStateEventAcceptedDefaultText = "@%s accepted your contact request"
const incomingMutualStateEventRemovedDefaultText = "@%s removed you as a contact"

var ErrGetLatestContactRequestForContactInvalidID = errors.New("get-latest-contact-request-for-contact: invalid id")

type SelfContactChangeEvent struct {
	DisplayNameChanged   bool
	PreferredNameChanged bool
	BioChanged           bool
	SocialLinksChanged   bool
	ImagesChanged        bool
}

func (m *Messenger) prepareMutualStateUpdateMessage(contactID string, updateType MutualStateUpdateType, clock uint64, timestamp uint64, outgoing bool) (*common.Message, error) {
	var text string
	var to string
	var from string
	var contentType protobuf.ChatMessage_ContentType
	if outgoing {
		to = contactID
		from = m.myHexIdentity()

		switch updateType {
		case MutualStateUpdateTypeSent:
			text = fmt.Sprintf(outgoingMutualStateEventSentDefaultText, contactID)
			contentType = protobuf.ChatMessage_SYSTEM_MESSAGE_MUTUAL_EVENT_SENT
		case MutualStateUpdateTypeAdded:
			text = fmt.Sprintf(outgoingMutualStateEventAcceptedDefaultText, contactID)
			contentType = protobuf.ChatMessage_SYSTEM_MESSAGE_MUTUAL_EVENT_ACCEPTED
		case MutualStateUpdateTypeRemoved:
			text = fmt.Sprintf(outgoingMutualStateEventRemovedDefaultText, contactID)
			contentType = protobuf.ChatMessage_SYSTEM_MESSAGE_MUTUAL_EVENT_REMOVED
		default:
			return nil, fmt.Errorf("unhandled outgoing MutualStateUpdateType = %d", updateType)
		}
	} else {
		to = m.myHexIdentity()
		from = contactID

		switch updateType {
		case MutualStateUpdateTypeSent:
			text = fmt.Sprintf(incomingMutualStateEventSentDefaultText, contactID)
			contentType = protobuf.ChatMessage_SYSTEM_MESSAGE_MUTUAL_EVENT_SENT
		case MutualStateUpdateTypeAdded:
			text = fmt.Sprintf(incomingMutualStateEventAcceptedDefaultText, contactID)
			contentType = protobuf.ChatMessage_SYSTEM_MESSAGE_MUTUAL_EVENT_ACCEPTED
		case MutualStateUpdateTypeRemoved:
			text = fmt.Sprintf(incomingMutualStateEventRemovedDefaultText, contactID)
			contentType = protobuf.ChatMessage_SYSTEM_MESSAGE_MUTUAL_EVENT_REMOVED
		default:
			return nil, fmt.Errorf("unhandled incoming MutualStateUpdateType = %d", updateType)
		}
	}

	message := &common.Message{
		ChatMessage: &protobuf.ChatMessage{
			ChatId:      contactID,
			Text:        text,
			MessageType: protobuf.MessageType_ONE_TO_ONE,
			ContentType: contentType,
			Clock:       clock,
			Timestamp:   timestamp,
		},
		From:             from,
		WhisperTimestamp: timestamp,
		LocalChatID:      contactID,
		Seen:             true,
		ID:               types.EncodeHex(crypto.Keccak256([]byte(fmt.Sprintf("%s%s%d%d", from, to, updateType, clock)))),
	}

	return message, nil
}

func (m *Messenger) acceptContactRequest(ctx context.Context, requestID string, fromSyncing bool) (*MessengerResponse, error) {
	contactRequest, err := m.persistence.MessageByID(requestID)
	if err != nil {
		m.logger.Error("could not find contact request message", zap.Error(err))
		return nil, err
	}

	m.logger.Info("acceptContactRequest")

	var ensName, nickname, displayName string
	customizationColor := multiaccountscommon.IDToColorFallbackToBlue(contactRequest.CustomizationColor)

	if contact, ok := m.allContacts.Load(contactRequest.From); ok {
		ensName = contact.EnsName
		nickname = contact.LocalNickname
		displayName = contact.DisplayName
		customizationColor = contact.CustomizationColor
	}

	response, err := m.addContact(ctx, contactRequest.From, ensName, nickname, displayName, customizationColor, contactRequest.ID, "", fromSyncing, false, false)
	if err != nil {
		return nil, err
	}

	// Force activate chat
	chat, ok := m.allChats.Load(contactRequest.From)
	if !ok {
		publicKey, err := common.HexToPubkey(contactRequest.From)
		if err != nil {
			return nil, err
		}

		chat = OneToOneFromPublicKey(publicKey, m.getTimesource())
	}

	chat.Active = true
	if err := m.saveChat(chat); err != nil {
		return nil, err
	}
	response.AddChat(chat)

	return response, nil
}

func (m *Messenger) AcceptContactRequest(ctx context.Context, request *requests.AcceptContactRequest) (*MessengerResponse, error) {
	err := request.Validate()
	if err != nil {
		return nil, err
	}

	response, err := m.acceptContactRequest(ctx, request.ID.String(), false)
	if err != nil {
		return nil, err
	}

	err = m.syncContactRequestDecision(ctx, request.ID.String(), "", true, m.dispatchMessage)
	if err != nil {
		return nil, err
	}

	return response, nil
}

func (m *Messenger) declineContactRequest(requestID, contactID string, fromSyncing bool) (*MessengerResponse, error) {
	m.logger.Info("declineContactRequest")

	contactRequest, err := m.persistence.MessageByID(requestID)
	if err == common.ErrRecordNotFound && fromSyncing {
		// original requestID(Message ID) is useless since we don't sync UserMessage in this case
		requestID = defaultContactRequestID(contactID)
		contactRequest, err = m.persistence.MessageByID(requestID)
	}
	if err != nil {
		return nil, err
	}

	response := &MessengerResponse{}
	var contact *Contact
	if contactRequest != nil {
		contact, err = m.BuildContact(&requests.BuildContact{PublicKey: contactRequest.From})
		if err != nil {
			return nil, err
		}
		contactRequest.ContactRequestState = common.ContactRequestStateDismissed
		err = m.persistence.SetContactRequestState(contactRequest.ID, contactRequest.ContactRequestState)
		if err != nil {
			return nil, err
		}
		response.AddMessage(contactRequest)
	}

	if !fromSyncing {
		_, clock, err := m.getOneToOneAndNextClock(contact)
		if err != nil {
			return nil, err
		}

		contact.DismissContactRequest(clock)
		err = m.persistence.SaveContact(contact, nil)
		if err != nil {
			return nil, err
		}

		response.AddContact(contact)
	}

	// update notification with the correct status
	notification, err := m.persistence.GetActivityCenterNotificationByID(types.FromHex(requestID))
	if err != nil {
		return nil, err
	}
	if notification != nil {
		notification.Name = contact.PrimaryName()
		notification.Message = contactRequest
		notification.Read = true
		notification.Dismissed = true
		notification.UpdatedAt = m.GetCurrentTimeInMillis()

		err = m.addActivityCenterNotification(response, notification, m.syncActivityCenterDismissedByIDs)
		if err != nil {
			m.logger.Error("failed to save notification", zap.Error(err))
			return nil, err
		}
	}
	return response, nil
}

func (m *Messenger) DeclineContactRequest(ctx context.Context, request *requests.DeclineContactRequest) (*MessengerResponse, error) {
	err := request.Validate()
	if err != nil {
		return nil, err
	}

	response, err := m.declineContactRequest(request.ID.String(), "", false)
	if err != nil {
		return nil, err
	}

	err = m.syncContactRequestDecision(ctx, request.ID.String(), "", false, m.dispatchMessage)
	if err != nil {
		return nil, err
	}

	return response, nil
}

func (m *Messenger) SendContactRequest(ctx context.Context, request *requests.SendContactRequest) (*MessengerResponse, error) {
	err := request.Validate()
	if err != nil {
		return nil, err
	}

	chatID, err := request.HexID()
	if err != nil {
		return nil, err
	}

	var ensName, nickname, displayName string
	customizationColor := multiaccountscommon.CustomizationColorBlue

	if contact, ok := m.allContacts.Load(chatID); ok {
		ensName = contact.EnsName
		nickname = contact.LocalNickname
		displayName = contact.DisplayName
		customizationColor = contact.CustomizationColor
	}

	return m.addContact(
		ctx,
		chatID,
		ensName,
		nickname,
		displayName,
		customizationColor,
		"",
		request.Message,
		false,
		false,
		true,
	)
}

func (m *Messenger) updateAcceptedContactRequest(response *MessengerResponse, contactRequestID, contactID string, fromSyncing bool) (*MessengerResponse, error) {
	m.logger.Debug("updateAcceptedContactRequest", zap.String("contactRequestID", contactRequestID), zap.String("contactID", contactID), zap.Bool("fromSyncing", fromSyncing))

	contactRequest, err := m.persistence.MessageByID(contactRequestID)
	if err == common.ErrRecordNotFound && fromSyncing {
		// original requestID(Message ID) is useless since we don't sync UserMessage in this case
		contactRequestID = defaultContactRequestID(contactID)
		contactRequest, err = m.persistence.MessageByID(contactRequestID)
	}
	if err != nil {
		m.logger.Error("contact request not found", zap.String("contactRequestID", contactRequestID), zap.Error(err))
		return nil, err
	}

	contactRequest.ContactRequestState = common.ContactRequestStateAccepted

	err = m.persistence.SetContactRequestState(contactRequest.ID, contactRequest.ContactRequestState)
	if err != nil {
		return nil, err
	}

	contact, ok := m.allContacts.Load(contactRequest.From)
	if !ok {
		m.logger.Error("failed to update contact request: contact not found", zap.String("contact id", contactRequest.From))
		return nil, errors.New("failed to update contact request: contact not found")
	}

	chat, ok := m.allChats.Load(contact.ID)
	if !ok {
		return nil, errors.New("no chat found for accepted contact request")
	}

	notification, err := m.persistence.GetActivityCenterNotificationByID(types.FromHex(contactRequest.ID))
	if err != nil {
		return nil, err
	}

	clock, _ := chat.NextClockAndTimestamp(m.transport)
	contact.AcceptContactRequest(clock)

	if !fromSyncing {
		acceptContactRequest := &protobuf.AcceptContactRequest{
			Id:    contactRequest.ID,
			Clock: clock,
		}
		encodedMessage, err := proto.Marshal(acceptContactRequest)
		if err != nil {
			return nil, err
		}
		_, err = m.dispatchMessage(context.Background(), common.RawMessage{
			LocalChatID: contactRequest.From,
			Payload:     encodedMessage,
			MessageType: protobuf.ApplicationMetadataMessage_ACCEPT_CONTACT_REQUEST,
			ResendType:  common.ResendTypeDataSync,
		})
		if err != nil {
			return nil, err
		}

		// Dispatch profile message to add a contact to the encrypted profile part
		err = m.DispatchProfileShowcase()
		if err != nil {
			return nil, err
		}
	}

	if response == nil {
		response = &MessengerResponse{}
	}

	if notification != nil {
		notification.Name = contact.PrimaryName()
		notification.Message = contactRequest
		notification.Read = true
		notification.Accepted = true
		notification.UpdatedAt = m.GetCurrentTimeInMillis()

		err = m.addActivityCenterNotification(response, notification, nil)
		if err != nil {
			m.logger.Error("failed to save notification", zap.Error(err))
			return nil, err
		}
	}

	response.AddMessage(contactRequest)
	response.AddContact(contact)

	// Add mutual state update message for incoming contact request
	clock, timestamp := chat.NextClockAndTimestamp(m.transport)
	updateMessage, err := m.prepareMutualStateUpdateMessage(contact.ID, MutualStateUpdateTypeAdded, clock, timestamp, true)
	if err != nil {
		return nil, err
	}

	err = m.prepareMessage(updateMessage, m.httpServer)
	if err != nil {
		return nil, err
	}
	err = m.persistence.SaveMessages([]*common.Message{updateMessage})
	if err != nil {
		return nil, err
	}
	response.AddMessage(updateMessage)
	response.AddChat(chat)

	return response, nil
}

func (m *Messenger) addContact(ctx context.Context,
	pubKey, ensName, nickname, displayName string,
	customizationColor multiaccountscommon.CustomizationColor,
	contactRequestID, contactRequestText string,
	fromSyncing, sendContactUpdate, createOutgoingContactRequestNotification bool) (*MessengerResponse, error) {
	contact, err := m.BuildContact(&requests.BuildContact{PublicKey: pubKey})
	if err != nil {
		return nil, err
	}

	response := &MessengerResponse{}

	chat, clock, err := m.getOneToOneAndNextClock(contact)
	if err != nil {
		return nil, err
	}

	if ensName != "" {
		err := m.ensVerifier.ENSVerified(pubKey, ensName, clock)
		if err != nil {
			return nil, err
		}
	}
	if err := m.addENSNameToContact(contact); err != nil {
		return nil, err
	}

	if len(nickname) != 0 {
		contact.LocalNickname = nickname
	}

	if len(displayName) != 0 {
		contact.DisplayName = displayName
	}

	contact.CustomizationColor = customizationColor

	contact.LastUpdatedLocally = clock
	contact.ContactRequestSent(clock)

	if !fromSyncing {
		// We sync the contact with the other devices
		err := m.syncContact(context.Background(), contact, m.dispatchMessage)
		if err != nil {
			return nil, err
		}
	}

	err = m.persistence.SaveContact(contact, nil)
	if err != nil {
		return nil, err
	}

	// TODO(samyoul) remove storing of an updated reference pointer?
	m.allContacts.Store(contact.ID, contact)

	// And we re-register for push notications
	err = m.reregisterForPushNotifications()
	if err != nil {
		return nil, err
	}

	// Reset last published time for ChatIdentity so new contact can receive data
	err = m.resetLastPublishedTimeForChatIdentity()
	if err != nil {
		return nil, err
	}

	// Profile chats are deprecated.
	// Code below can be removed after some reasonable time.

	//Create the corresponding chat
	var profileChat *Chat
	if !deprecation.ChatProfileDeprecated {
		profileChat = m.buildProfileChat(contact.ID)

		_, err = m.Join(profileChat)
		if err != nil {
			return nil, err
		}

		if err := m.saveChat(profileChat); err != nil {
			return nil, err
		}
	}

	publicKey, err := contact.PublicKey()
	if err != nil {
		return nil, err
	}

	// Fetch contact code
	_, err = m.scheduleSyncFiltersForContact(publicKey)
	if err != nil {
		return nil, err
	}

	if sendContactUpdate {
		// Get ENS name of a current user
		ensName, err = m.settings.ENSName()
		if err != nil {
			return nil, err
		}

		// Get display name of a current user
		displayName, err = m.settings.DisplayName()
		if err != nil {
			return nil, err
		}
		response, err = m.sendContactUpdate(context.Background(), pubKey, displayName, ensName, "", m.account.GetCustomizationColor(), m.dispatchMessage)
		if err != nil {
			return nil, err
		}
	}

	if len(contactRequestID) != 0 {
		updatedResponse, err := m.updateAcceptedContactRequest(response, contactRequestID, "", false)
		if err != nil {
			return nil, err
		}
		err = response.Merge(updatedResponse)
		if err != nil {
			return nil, err
		}
	}

	// Sends a standalone ChatIdentity message
	err = m.handleStandaloneChatIdentity(chat)
	if err != nil {
		return nil, err
	}

	// Profile chats are deprecated.
	// Code below can be removed after some reasonable time.

	// Add chat
	if !deprecation.ChatProfileDeprecated {
		response.AddChat(profileChat)

		_, err = m.transport.InitFilters([]transport.FiltersToInitialize{{ChatID: profileChat.ID}}, []*ecdsa.PublicKey{publicKey})
		if err != nil {
			return nil, err
		}
	}

	// Publish contact code
	err = m.publishContactCode()
	if err != nil {
		return nil, err
	}

	// Add mutual state update message for outgoing contact request
	if len(contactRequestID) == 0 {
		clock, timestamp := chat.NextClockAndTimestamp(m.transport)
		updateMessage, err := m.prepareMutualStateUpdateMessage(contact.ID, MutualStateUpdateTypeSent, clock, timestamp, true)
		if err != nil {
			return nil, err
		}

		err = m.prepareMessage(updateMessage, m.httpServer)
		if err != nil {
			return nil, err
		}
		err = m.persistence.SaveMessages([]*common.Message{updateMessage})
		if err != nil {
			return nil, err
		}
		response.AddMessage(updateMessage)
		err = chat.UpdateFromMessage(updateMessage, m.getTimesource())
		if err != nil {
			return nil, err
		}
		response.AddChat(chat)
	}

	// Add outgoing contact request notification
	if createOutgoingContactRequestNotification {
		clock, timestamp := chat.NextClockAndTimestamp(m.transport)
		contactRequest, err := m.generateContactRequest(clock, timestamp, contact, contactRequestText, true)
		if err != nil {
			return nil, err
		}

		// Send contact request as a plain chat message
		messageResponse, err := m.sendChatMessage(ctx, contactRequest)
		if err != nil {
			return nil, err
		}

		err = response.Merge(messageResponse)
		if err != nil {
			return nil, err
		}

		notification := m.generateOutgoingContactRequestNotification(contact, contactRequest)
		err = m.addActivityCenterNotification(response, notification, nil)
		if err != nil {
			return nil, err
		}
	}

	// Add contact
	response.AddContact(contact)
	return response, nil
}

func (m *Messenger) generateContactRequest(clock uint64, timestamp uint64, contact *Contact, text string, outgoing bool) (*common.Message, error) {
	if contact == nil {
		return nil, errors.New("contact cannot be nil")
	}

	contactRequest := common.NewMessage()
	contactRequest.ChatId = contact.ID
	contactRequest.WhisperTimestamp = timestamp
	contactRequest.Seen = true
	contactRequest.Text = text
	if outgoing {
		contactRequest.From = m.myHexIdentity()
		contactRequest.CustomizationColor = m.account.GetCustomizationColorID()
	} else {
		contactRequest.From = contact.ID
		contactRequest.CustomizationColor = multiaccountscommon.ColorToIDFallbackToBlue(contact.CustomizationColor)
	}
	contactRequest.LocalChatID = contact.ID
	contactRequest.ContentType = protobuf.ChatMessage_CONTACT_REQUEST
	contactRequest.Clock = clock
	if contact.mutual() {
		contactRequest.ContactRequestState = common.ContactRequestStateAccepted
	} else {
		contactRequest.ContactRequestState = common.ContactRequestStatePending
	}
	err := contactRequest.PrepareContent(common.PubkeyToHex(&m.identity.PublicKey))
	return contactRequest, err
}

func (m *Messenger) generateOutgoingContactRequestNotification(contact *Contact, contactRequest *common.Message) *ActivityCenterNotification {
	return &ActivityCenterNotification{
		ID:        types.FromHex(contactRequest.ID),
		Type:      ActivityCenterNotificationTypeContactRequest,
		Name:      contact.PrimaryName(),
		Author:    m.myHexIdentity(),
		Message:   contactRequest,
		Timestamp: m.getTimesource().GetCurrentTime(),
		ChatID:    contact.ID,
		Read: contactRequest.ContactRequestState == common.ContactRequestStateAccepted ||
			contactRequest.ContactRequestState == common.ContactRequestStateDismissed ||
			contactRequest.ContactRequestState == common.ContactRequestStatePending,
		Accepted:  contactRequest.ContactRequestState == common.ContactRequestStateAccepted,
		Dismissed: contactRequest.ContactRequestState == common.ContactRequestStateDismissed,
		UpdatedAt: m.GetCurrentTimeInMillis(),
	}
}

func (m *Messenger) AddContact(ctx context.Context, request *requests.AddContact) (*MessengerResponse, error) {
	err := request.Validate()
	if err != nil {
		return nil, err
	}

	id, err := request.HexID()
	if err != nil {
		return nil, err
	}

	return m.addContact(
		ctx,
		id,
		request.ENSName,
		request.Nickname,
		request.DisplayName,
		multiaccountscommon.CustomizationColor(request.CustomizationColor),
		"",
		defaultContactRequestText(),
		false,
		true,
		true,
	)
}

func (m *Messenger) resetLastPublishedTimeForChatIdentity() error {
	// Reset last published time for ChatIdentity so new contact can receive data
	contactCodeTopic := transport.ContactCodeTopic(&m.identity.PublicKey)
	m.logger.Debug("contact state changed ResetWhenChatIdentityLastPublished")
	return m.persistence.ResetWhenChatIdentityLastPublished(contactCodeTopic)
}

func (m *Messenger) removeContact(ctx context.Context, response *MessengerResponse, pubKey string, sync bool) error {
	contact, ok := m.allContacts.Load(pubKey)
	if !ok {
		return ErrContactNotFound
	}

	// System message for mutual state update
	chat, clock, err := m.getOneToOneAndNextClock(contact)
	if err != nil {
		return err
	}
	timestamp := m.getTimesource().GetCurrentTime()
	updateMessage, err := m.prepareMutualStateUpdateMessage(contact.ID, MutualStateUpdateTypeRemoved, clock, timestamp, true)
	if err != nil {
		return err
	}

	err = m.prepareMessage(updateMessage, m.httpServer)
	if err != nil {
		return err
	}
	err = m.persistence.SaveMessages([]*common.Message{updateMessage})
	if err != nil {
		return err
	}
	response.AddMessage(updateMessage)
	err = chat.UpdateFromMessage(updateMessage, m.getTimesource())
	if err != nil {
		return err
	}
	response.AddChat(chat)

	// Next we retract a contact request
	contact.RetractContactRequest(clock)
	contact.LastUpdatedLocally = m.getTimesource().GetCurrentTime()

	err = m.persistence.SaveContact(contact, nil)
	if err != nil {
		return err
	}

	if sync {
		err = m.syncContact(context.Background(), contact, m.dispatchMessage)
		if err != nil {
			return err
		}
	}

	// TODO(samyoul) remove storing of an updated reference pointer?
	m.allContacts.Store(contact.ID, contact)

	// And we re-register for push notications
	err = m.reregisterForPushNotifications()
	if err != nil {
		return err
	}

	// Dispatch profile message to remove a contact from the encrypted profile part
	err = m.DispatchProfileShowcase()
	if err != nil {
		return err
	}

	// Profile chats are deprecated.
	// Code below can be removed after some reasonable time.

	//Create the corresponding profile chat
	if !deprecation.ChatProfileDeprecated {
		profileChatID := buildProfileChatID(contact.ID)
		_, ok = m.allChats.Load(profileChatID)

		if ok {
			chatResponse, err := m.deactivateChat(profileChatID, 0, false, true)
			if err != nil {
				return err
			}
			err = response.Merge(chatResponse)
			if err != nil {
				return err
			}
		}
	}

	response.Contacts = []*Contact{contact}
	return nil
}

func (m *Messenger) RemoveContact(ctx context.Context, pubKey string) (*MessengerResponse, error) {
	response := new(MessengerResponse)

	err := m.removeContact(ctx, response, pubKey, true)
	if err != nil {
		return nil, err
	}

	return response, nil
}

func (m *Messenger) updateContactImagesURL(contact *Contact) error {
	if m.httpServer != nil {
		for k, v := range contact.Images {
			publicKey, err := contact.PublicKey()
			if err != nil {
				return err
			}
			v.LocalURL = m.httpServer.MakeContactImageURL(common.PubkeyToHex(publicKey), k)
			contact.Images[k] = v
		}
	}
	return nil
}

func (m *Messenger) Contacts() []*Contact {
	var contacts []*Contact
	m.allContacts.Range(func(contactID string, contact *Contact) (shouldContinue bool) {
		contacts = append(contacts, contact)
		return true
	})
	return contacts
}

func (m *Messenger) AddedContacts() []*Contact {
	var contacts []*Contact
	m.allContacts.Range(func(contactID string, contact *Contact) (shouldContinue bool) {
		if contact.added() {
			contacts = append(contacts, contact)
		}
		return true
	})
	return contacts
}

func (m *Messenger) MutualContacts() []*Contact {
	var contacts []*Contact
	m.allContacts.Range(func(contactID string, contact *Contact) (shouldContinue bool) {
		if contact.mutual() {
			contacts = append(contacts, contact)
		}
		return true
	})
	return contacts
}

func (m *Messenger) BlockedContacts() []*Contact {
	var contacts []*Contact
	m.allContacts.Range(func(contactID string, contact *Contact) (shouldContinue bool) {
		if contact.Blocked {
			contacts = append(contacts, contact)
		}
		return true
	})
	return contacts
}

// GetContactByID returns a Contact for given pubKey, if it's known.
// This function automatically checks if pubKey is self identity key and returns a Contact
// filled with self information.
// pubKey is assumed to include `0x` prefix
func (m *Messenger) GetContactByID(pubKey string) *Contact {
	if pubKey == m.IdentityPublicKeyString() {
		return m.selfContact
	}
	contact, _ := m.allContacts.Load(pubKey)
	return contact
}

func (m *Messenger) GetSelfContact() *Contact {
	return m.selfContact
}

func (m *Messenger) SetContactLocalNickname(request *requests.SetContactLocalNickname) (*MessengerResponse, error) {

	if err := request.Validate(); err != nil {
		return nil, err
	}

	pubKey := request.ID.String()
	nickname := request.Nickname

	contact, err := m.BuildContact(&requests.BuildContact{PublicKey: pubKey})
	if err != nil {
		return nil, err
	}

	if err := m.addENSNameToContact(contact); err != nil {
		return nil, err
	}

	clock := m.getTimesource().GetCurrentTime()
	contact.LocalNickname = nickname
	contact.LastUpdatedLocally = clock

	err = m.persistence.SaveContact(contact, nil)
	if err != nil {
		return nil, err
	}

	m.allContacts.Store(contact.ID, contact)

	response := &MessengerResponse{}
	response.Contacts = []*Contact{contact}

	err = m.syncContact(context.Background(), contact, m.dispatchMessage)
	if err != nil {
		return nil, err
	}

	return response, nil
}

func (m *Messenger) blockContact(ctx context.Context, response *MessengerResponse, contactID string, isDesktopFunc bool, fromSyncing bool) error {
	contact, err := m.BuildContact(&requests.BuildContact{PublicKey: contactID})
	if err != nil {
		return err
	}

	response.AddContact(contact)

	_, clock, err := m.getOneToOneAndNextClock(contact)
	if err != nil {
		return err
	}

	contactWasAdded := contact.added()
	contact.Block(clock)

	contact.LastUpdatedLocally = m.getTimesource().GetCurrentTime()

	chats, err := m.persistence.BlockContact(contact, isDesktopFunc)
	if err != nil {
		return err
	}

	response.AddChats(chats)

	m.allContacts.Store(contact.ID, contact)
	for _, chat := range chats {
		m.allChats.Store(chat.ID, chat)
	}

	if !isDesktopFunc {
		m.allChats.Delete(contact.ID)
		m.allChats.Delete(buildProfileChatID(contact.ID))
	}

	if !fromSyncing {
		if contactWasAdded {
			err = m.sendRetractContactRequest(contact)
			if err != nil {
				return err
			}
		}

		err = m.syncContact(context.Background(), contact, m.dispatchMessage)
		if err != nil {
			return err
		}

		// We remove anything that's related to this contact request
		updatedAt := m.GetCurrentTimeInMillis()
		notifications, err := m.persistence.DeleteChatContactRequestActivityCenterNotifications(contact.ID, updatedAt)
		if err != nil {
			return err
		}
		err = m.syncActivityCenterDeleted(ctx, notifications, updatedAt)
		if err != nil {
			m.logger.Error("BlockContact, error syncing activity center notifications as deleted", zap.Error(err))
			return err
		}
	}

	// re-register for push notifications
	err = m.reregisterForPushNotifications()
	if err != nil {
		return err
	}

	return nil
}

func (m *Messenger) BlockContact(ctx context.Context, contactID string, fromSyncing bool) (*MessengerResponse, error) {
	response := &MessengerResponse{}

	err := m.blockContact(ctx, response, contactID, false, fromSyncing)
	if err != nil {
		return nil, err
	}

	response, err = m.DeclineAllPendingGroupInvitesFromUser(ctx, response, contactID)
	if err != nil {
		return nil, err
	}

	// AC notifications are synced separately
	// NOTE: Should we still do the local part (persistence.dismiss...) and only skip the syncing?
	//		 This would make the solution more reliable even in case AC notification sync is not recevied.
	//		 This should be considered separately, I'm not sure if that's safe.
	//		 https://github.com/status-im/status-go/issues/3720
	if !fromSyncing {
		updatedAt := m.GetCurrentTimeInMillis()
		_, err = m.DismissAllActivityCenterNotificationsFromUser(ctx, contactID, updatedAt)
		if err != nil {
			return nil, err
		}
	}

	return response, nil
}

// The same function as the one above.
// Should be removed with https://github.com/status-im/status-desktop/issues/8805
func (m *Messenger) BlockContactDesktop(ctx context.Context, contactID string) (*MessengerResponse, error) {
	response := &MessengerResponse{}

	err := m.blockContact(ctx, response, contactID, true, false)
	if err != nil {
		return nil, err
	}

	response, err = m.DeclineAllPendingGroupInvitesFromUser(ctx, response, contactID)
	if err != nil {
		return nil, err
	}

	notifications, err := m.DismissAllActivityCenterNotificationsFromUser(ctx, contactID, m.GetCurrentTimeInMillis())
	if err != nil {
		return nil, err
	}
	response.AddActivityCenterNotifications(notifications)
	return response, nil
}

func (m *Messenger) UnblockContact(contactID string) (*MessengerResponse, error) {
	response := &MessengerResponse{}
	contact, ok := m.allContacts.Load(contactID)
	if !ok || !contact.Blocked {
		return response, nil
	}

	_, clock, err := m.getOneToOneAndNextClock(contact)
	if err != nil {
		return nil, err
	}

	contact.Unblock(clock)

	contact.LastUpdatedLocally = m.getTimesource().GetCurrentTime()

	err = m.persistence.SaveContact(contact, nil)
	if err != nil {
		return nil, err
	}

	m.allContacts.Store(contact.ID, contact)

	response.AddContact(contact)

	err = m.syncContact(context.Background(), contact, m.dispatchMessage)
	if err != nil {
		return nil, err
	}

	// re-register for push notifications
	err = m.reregisterForPushNotifications()
	if err != nil {
		return nil, err
	}

	return response, nil
}

// Send contact updates to all contacts added by us
func (m *Messenger) SendContactUpdates(ctx context.Context, ensName, profileImage string, customizationColor multiaccountscommon.CustomizationColor) (err error) {
	myID := contactIDFromPublicKey(&m.identity.PublicKey)

	displayName, err := m.settings.DisplayName()
	if err != nil {
		return err
	}

	if len(customizationColor) == 0 && m.account != nil {
		customizationColor = m.account.GetCustomizationColor()
	}

	if _, err = m.sendContactUpdate(ctx, myID, displayName, ensName, profileImage, customizationColor, m.dispatchMessage); err != nil {
		return err
	}

	// TODO: This should not be sending paired messages, as we do it above
	m.allContacts.Range(func(contactID string, contact *Contact) (shouldContinue bool) {
		if contact.added() {
			if _, err = m.sendContactUpdate(ctx, contact.ID, displayName, ensName, profileImage, customizationColor, m.dispatchMessage); err != nil {
				return false
			}
		}
		return true
	})
	return err
}

// NOTE: this endpoint does not add the contact, the reason being is that currently
// that's left as a responsibility to the client, which will call both `SendContactUpdate`
// and `SaveContact` with the correct system tag.
// Ideally we have a single endpoint that does both, but probably best to bring `ENS` name
// on the messenger first.

// SendContactUpdate sends a contact update to a user and adds the user to contacts
func (m *Messenger) SendContactUpdate(ctx context.Context, chatID, ensName, profileImage string, customizationColor multiaccountscommon.CustomizationColor) (*MessengerResponse, error) {
	displayName, err := m.settings.DisplayName()
	if err != nil {
		return nil, err
	}

	return m.sendContactUpdate(ctx, chatID, displayName, ensName, profileImage, customizationColor, m.dispatchMessage)
}

func (m *Messenger) sendContactUpdate(ctx context.Context,
	chatID, displayName, ensName, profileImage string,
	customizationColor multiaccountscommon.CustomizationColor,
	rawMessageHandler RawMessageHandler) (*MessengerResponse, error) {
	var response MessengerResponse

	contact, ok := m.allContacts.Load(chatID)
	if !ok || !contact.added() {
		return nil, nil
	}

	chat, clock, err := m.getOneToOneAndNextClock(contact)
	if err != nil {
		return nil, err
	}

	contactUpdate := &protobuf.ContactUpdate{
		Clock:                         clock,
		DisplayName:                   displayName,
		EnsName:                       ensName,
		ProfileImage:                  profileImage,
		ContactRequestClock:           contact.ContactRequestLocalClock,
		ContactRequestPropagatedState: contact.ContactRequestPropagatedState(),
		PublicKey:                     contact.ID,
		CustomizationColor:            multiaccountscommon.ColorToIDFallbackToBlue(customizationColor),
	}

	encodedMessage, err := proto.Marshal(contactUpdate)
	if err != nil {
		return nil, err
	}

	rawMessage := common.RawMessage{
		LocalChatID: chatID,
		Payload:     encodedMessage,
		MessageType: protobuf.ApplicationMetadataMessage_CONTACT_UPDATE,
		ResendType:  common.ResendTypeDataSync,
	}

	_, err = rawMessageHandler(ctx, rawMessage)
	if err != nil {
		return nil, err
	}

	response.Contacts = []*Contact{contact}
	response.AddChat(chat)

	chat.LastClockValue = clock
	err = m.saveChat(chat)
	if err != nil {
		return nil, err
	}
	return &response, nil
}

func (m *Messenger) addENSNameToContact(contact *Contact) error {

	// Check if there's already a verified record
	ensRecord, err := m.ensVerifier.GetVerifiedRecord(contact.ID)
	if err != nil {
		return err
	}
	if ensRecord == nil {
		return nil
	}

	contact.EnsName = ensRecord.Name
	contact.ENSVerified = true

	return nil
}

func (m *Messenger) RetractContactRequest(request *requests.RetractContactRequest) (*MessengerResponse, error) {
	err := request.Validate()
	if err != nil {
		return nil, err
	}
	contact, ok := m.allContacts.Load(request.ID.String())
	if !ok {
		return nil, errors.New("contact not found")
	}
	response := &MessengerResponse{}
	err = m.removeContact(context.Background(), response, contact.ID, true)
	if err != nil {
		return nil, err
	}

	err = m.sendRetractContactRequest(contact)
	if err != nil {
		return nil, err
	}

	return response, err
}

// Send message to remote account to remove our contact from their end.
func (m *Messenger) sendRetractContactRequest(contact *Contact) error {
	_, clock, err := m.getOneToOneAndNextClock(contact)
	if err != nil {
		return err
	}
	retractContactRequest := &protobuf.RetractContactRequest{
		Clock: clock,
	}

	encodedMessage, err := proto.Marshal(retractContactRequest)
	if err != nil {
		return err
	}

	_, err = m.dispatchMessage(context.Background(), common.RawMessage{
		LocalChatID: contact.ID,
		Payload:     encodedMessage,
		MessageType: protobuf.ApplicationMetadataMessage_RETRACT_CONTACT_REQUEST,
		ResendType:  common.ResendTypeDataSync,
	})
	if err != nil {
		return err
	}

	return err
}

func (m *Messenger) GetLatestContactRequestForContact(contactID string) (*MessengerResponse, error) {
	if len(contactID) == 0 {
		return nil, ErrGetLatestContactRequestForContactInvalidID
	}

	contactRequestID, err := m.persistence.LatestPendingContactRequestIDForContact(contactID)
	if err != nil {
		return nil, err
	}

	contactRequest, err := m.persistence.MessageByID(contactRequestID)
	if err != nil {
		m.logger.Error("contact request not found", zap.String("contactRequestID", contactRequestID), zap.Error(err))
		return nil, err
	}

	response := &MessengerResponse{}
	response.AddMessage(contactRequest)

	return response, nil
}

func (m *Messenger) AcceptLatestContactRequestForContact(ctx context.Context, request *requests.AcceptLatestContactRequestForContact) (*MessengerResponse, error) {
	if err := request.Validate(); err != nil {
		return nil, err
	}

	contactRequestID, err := m.persistence.LatestPendingContactRequestIDForContact(request.ID.String())
	if err != nil {
		return nil, err
	}

	return m.AcceptContactRequest(ctx, &requests.AcceptContactRequest{ID: types.Hex2Bytes(contactRequestID)})
}

func (m *Messenger) DismissLatestContactRequestForContact(ctx context.Context, request *requests.DismissLatestContactRequestForContact) (*MessengerResponse, error) {
	if err := request.Validate(); err != nil {
		return nil, err
	}

	contactRequestID, err := m.persistence.LatestPendingContactRequestIDForContact(request.ID.String())
	if err != nil {
		return nil, err
	}

	return m.DeclineContactRequest(ctx, &requests.DeclineContactRequest{ID: types.Hex2Bytes(contactRequestID)})
}

func (m *Messenger) PendingContactRequests(cursor string, limit int) ([]*common.Message, string, error) {
	return m.persistence.PendingContactRequests(cursor, limit)
}

func defaultContactRequestID(contactID string) string {
	return "0x" + types.Bytes2Hex(append(types.Hex2Bytes(contactID), 0x20))
}

func defaultContactRequestText() string {
	return "Please add me to your contacts"
}

func (m *Messenger) BuildContact(request *requests.BuildContact) (*Contact, error) {
	contact, ok := m.allContacts.Load(request.PublicKey)
	if !ok {
		var err error
		contact, err = buildContactFromPkString(request.PublicKey)
		if err != nil {
			return nil, err
		}

		if request.ENSName != "" {
			contact.ENSVerified = true
			contact.EnsName = request.ENSName
		}

		if len(contact.CustomizationColor) == 0 {
			contact.CustomizationColor = multiaccountscommon.CustomizationColorBlue
		}
	}

	// Schedule sync filter to fetch information about the contact
	publicKey, err := contact.PublicKey()
	if err != nil {
		return nil, err
	}

	_, err = m.scheduleSyncFiltersForContact(publicKey)
	if err != nil {
		return nil, err
	}

	return contact, nil
}

func (m *Messenger) scheduleSyncFiltersForContact(publicKey *ecdsa.PublicKey) (*transport.Filter, error) {
	filter, err := m.transport.JoinPrivate(publicKey)
	if err != nil {
		return nil, err
	}
	_, err = m.scheduleSyncFilters([]*transport.Filter{filter})
	if err != nil {
		return filter, err
	}
	return filter, nil
}

func (m *Messenger) FetchContact(contactID string, waitForResponse bool) (*Contact, error) {
	options := []StoreNodeRequestOption{
		WithWaitForResponseOption(waitForResponse),
	}
	contact, _, err := m.storeNodeRequestsManager.FetchContact(contactID, options)
	return contact, err
}

func (m *Messenger) SubscribeToSelfContactChanges() chan *SelfContactChangeEvent {
	s := make(chan *SelfContactChangeEvent, 10)
	m.selfContactSubscriptions = append(m.selfContactSubscriptions, s)
	return s
}

func (m *Messenger) publishSelfContactSubscriptions(event *SelfContactChangeEvent) {
	for _, s := range m.selfContactSubscriptions {
		select {
		case s <- event:
		default:
			logutils.ZapLogger().Warn("self contact subscription channel full, dropping message")
		}
	}
}